With development of a Long Term Evolution (LTE) mobile communications system, to enable an evolved system to provide a higher transmission rate with a shorter transmission delay, the evolved system gradually evolves into a system in which two base stations simultaneously provide services for user equipment (UE). A first base station (MeNB, Macro eNodeB) may split data to the UE by using a primary cell of a second base station (primary second cell, PSCell), or a PSCell may directly obtain data from a core network and transmit the data to the UE. Before the UE communicates with the PSCell, the UE may need to initiate a random access (RA) process to the PSCell, and the UE can communicate with the PSCell only after accessing the PSCell; if a radio link failure (RLF) occurs when the UE initiates the random access process, the UE reports an RLF failure notification to the first base station.
In the prior art, before the UE initiates a random access process, the first base station sends an RLF failure condition to the UE, where the RLF failure condition includes a preset maximum quantity of times the UE sends random access scrambling code in the random access process, and when a quantity of times the UE sends the random access scrambling code is greater than the preset maximum quantity of times, the UE reports an RLF failure to the first base station. The random access process initiated by the UE is classified into two types: a random access process initiated when the UE initially requests to access the PSCell, and a random access process subsequently initiated, after the UE successfully accesses the PSCell, to the PSCell again for another requirement such as obtaining an uplink resource. In the prior art, a same maximum quantity of times is used for the two types of random access processes; however, in actual application, a success rate of a random access process initially initiated by the UE is generally lower than a success rate of a random access process subsequently initiated by the UE. Therefore, if a same maximum quantity of times is used, the success rate of the random access process initially initiated by the UE may be reduced, and eventually, random access initiated to the PSCell by the UE fails, which is unfavorable to data transmission between the UE and the PSCell.
In addition, to ensure that quality of a radio link of the PSCell meets a data transmission requirement, the UE needs to perform radio link monitoring on the radio link of the PSCell; however, a condition for triggering the radio link monitoring is not specified in the prior art, so that the UE cannot control a time for enabling the radio link monitoring, and an essential function of the radio link monitoring cannot be implemented.